Promising antitumor activity has been demonstrated against thymidine- and hypoxanthine-deficient murine tumor cell lines as well as two human tumor xenograft models following treatment with LY231514. In this Phase 1 study of LY231514, 2 of 3 patients with pancreatic cancer have had partial responses. The current study is designed to gather information about the safety and efficacy of LY231514 in patients with pancreatic cancer and to evaluate the changes in the patient's quality of life. This protocol proposes to study patients with no prior chemotherapy for advanced disease who are treated with LY231514 at 600 mg/m2 every three weeks, administered as a 10-minute infusion intravenously on day 1 of a 21 day cycle. Up to 35 qualified patients will be enrolled on a two-stage sequential study with the possibility of stopping the trial early for either lack of efficacy or for unacceptable toxicity. 0521 Promising antitumor activity has been demonstrated against thymidine- and hypoxanthine-deficient murine tumor cell lines as well as two human tumor xenograft models following treatment with LY231514. This is designed to gather information about the safety and efficacy of LY231514 in patients with metastatic colorectal cancer. This protocol proposes to study patients with no prior chemotherapy for metastatic disease, who are treated every three weeks with LY231514 at 600 mg/m2 administered as a 10-minute infusion intravenously on Day 1 of a 21 day cycle. Up to 35 qualified patients will be enrolled in a two-stage sequential study with the possibility of stopping the trial early for either lack of efficacy or for unacceptable toxicity.